Synthesis, Characterization, Physical Properties and Applications of Metal Borides

There is a need to understand boron and boron chemistry of metals and non-metals. Boron is an electron-deficient atom in bonding and can react with other elements (except noble gases) to form stable compounds, namely B2H6, MgB2, AlB2, B4C, SiB3, BN, Cr2B, Fe3B, ZrB2, LaB6, etc. It forms tetrahedral, cage-type, trigonal and layered structures, etc. B–B bond can be of single (B–B), double (B = B) or triple (B≡B) types. In metal-rich borides, metal–metal interaction occurs. They are used as catalysts, imparting materials for mechanical, thermal and chemical stability, magnetic, superconducting and coating materials, etc. In this article, several ways of synthesis of metal borides and characterization techniques have been discussed. Also, the synthesis methods for nanostructured metal borides are elaborated. The properties (magnetism, electronic structure, electrical resistivity, optics) of some selected compounds of metal borides in addition to BN, CN are described. Lastly, the applications of selected borides are provided.